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The Immune System in Your Gut_Final

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>> Hi, welcome back. By now you probably notice the gut is a pretty magical place. This long tube is not just where we break down and assembly food, it's also the gatekeeper to the outside world. What does that mean? Because it's directly in contact with the outside world, the gut must sift through what's beneficial for the body and what's not. This is the reason why it houses a large majority of the body's immune system and why it's the largest immune organ. To put that in context, in this lecture we are going to talk about the immune system. The immune system is made up of cells, tissues, and organs. And just as I mentioned, the gut is the largest immune organ in the body. To be exact, 70 to 80% of the immune system resides in the gut. For things to work properly, the immune cells in your gut need to be able to sore through all you ingest and tell the difference between healthy bacteria and pathogens, toxins, and nutrients, and protect against anything else you don't want in your body. Immune function is one of the main jobs of the gut. The epithelial layer of the gut provides a physical barrier. In addition to that, the epithelial layer is lined with immune cells that area constantly surveying the land, making sure that we're healthy and thriving. To properly do their job, the trick here is that the intestinal wall must be permeable enough to let end nutrient and fluids, but strong enough to keep out unwanted particles and toxins and pathogens. It also needs to keep the good bacteria in the places it should be and out of the places it shouldn't, not an easy job. Goblet cells in the epithelial layer produce mucus. You recall that goblet cells serve to protect the gut wall from unwanted bacteria. This mucus lines the walls that contain pathogen killing substances called defensins. This is one of my favorite names because it's so obvious. The immune system starts in the mouth and runs along the length of the digestive system, at the root of the tongue, our dome-like structures what we know as the tonsils. Many people think that tonsils don't do much except get us a sick, but they're actually full of immune cells. The tonsils also seem to communicate with the immune system at large, educating, you know, what is friend and what's foe. This is also why they are likely to get infected as all immune cells are more vulnerable to flare-ups. Don't worry. Few like many of us have your tonsils out. We have tons of backup. Beyond the tonsils, you have your immune tissues surrounding your entire throat. They are more dome-like immune filled tissues along your gut lining in your small intestine called Peyer's patches. Peyer's patches are right below the epithelial layer in the lamina propria, they're like security guards monitoring all the happenings in the bacterial population of the gut so that the body is on full alert if anything or anyone suspicious shows up. In addition to functioning as a physical barrier, the immune system in the gut sends out chemical signals to identify and fight off unwanted substances. This is important to understand when considering gut problems because it's the immune system that triggers information or autoimmune reactions in response to these signals that picks up from the immune cells in the gut. There are three things immune cells do. One, they make more immune cells. Two, they produce cytokines which are signals that communicate between cells that can trigger inflammation and can also turn genes on and off. And three, they produce antibodies called adhesion molecules that can attach to a pathogen or an unwanted substance and lead it out of the body via the liver and spleen. An easy way to remember how antibodies work is to imagine them as plugs. When they do their job, they essentially plug up the antigen or unwanted substance so that it can't activate or attach to anything in the body. When conceptualizing immune function, it can be broken down into two parts. The innate immune system, the one we're born with and the adaptive immune system that learns and get smarter over time. You can think of the innate system as a set of instinctual immune responses and the adaptive immune system as a set of learned responses. It's much like I make up a behavior. The innate immune system is a bit like a hand grenade. Imagine a soldier holding the pin ready to release quickly and indiscriminately targeting anything in the area when time is of the utmost importance. Like when you have an open wound, there is no time to survey the land, the critical goal is to keep you alive and preserve your health. The innate immune system is triggered to quickly keep the area clean or rid it of infection. In the case of an open wound, the body is exposed and the innate immune system instinctively knows that the area must be protected, even if a few bystanders' healthy cells are injured in the process. White blood cells are part of the innate immune system. Since this system is located alongside of physical barrier, it takes a broad approach to defense. It's not super strong because there are other mechanisms in place to keep out unwanted intruders, such as, acid and enzymes in the gut. Think of the innate immune system as an anti-bacterial hand wash, generally cleaning out the area, weeding out many of the bad guys. As I mentioned earlier, the innate immune system targets three things. One, breaks in the physical barrier like in open wound. Two, foreign bodies like bacteria or pollens, and three, compromise cells like a cell that has become cancerous or invaded by a virus. Also, there are three major types of innate immune responses that we'll focus on. One, inflammation, two, phagocytes or pathogen-eating cells, and three, natural killer cells. The innate immune system is a key when it comes to allowing the body to act fast. Inflammatory cells kill invading pathogens by raising the body temperature to burn them off. Blood flow is increased and fever may occur, all is a way to protect the body by becoming too hot to trot. Inflammation is a response that helps protect the body against unfriendly bacteria and supports tissue repair. Similar to fight or flight, inflammation is a necessary response that only becomes problematic when it goes on for too long or the reaction is too strong. Why would this happen? Well, for example, if you are eating a food that creates an immune reaction, inflammation will occur to protect you from being irritated. It can also happen to protect you from harmful bacteria. Make sense, right? For a long time, the common wisdom was that children should be put on antibiotics or medication to bring a fever down, but now we are starting to understand the wisdom of letting a fever run its course and how fever can be a sign of the body doing its job well. Another way our body fights invaders is with phagocytes. These are like little pacman that go around gobbling the pathogens. And the third way of the innate immune system works is by creating what are called natural killer cells. These cells target any cell that's been overtaken by a virus or infection. When it's too late and the cells already gone to the dark side, the natural killer cells essentially pull the plug and kill off the cell to help restore the body. This is what is referred to as a change body. It was once a normal cell, but now when it's become infected, for the good of the whole it's no longer safe to keep this changed cell around. If this first line of defense is unsuccessful, about four to seven days later the body unleashes its second round of attacks, the adaptive immune system. You can think of these defenders of the body as the sharp shooters that can target specific pathogens or cells. The adaptive immune system is smart. It has a memory of cells that have created a previous offense in the past like a database of information. When a familiar threat is experienced, the body can look in its storage for the perfect antidote or antibody to ward off that offender. The adaptive immune system knows its enemy's weak points and uses that to formulate its strategy. Cool, right? This is why it can be slower than the innate immune system. It's calculated and if there is no memory stored, it takes the body awhile to figure out what to do. But previous offenders, watch out. It's got your number. These memory cells are the reason that some illnesses like chicken pox tend to happen only once. Vaccines also work on this system. And a vaccine inactive viruses or bacteria that may cause illness or introduce so that the body is warned and can properly fight off the infections when it's faced with them in the future. The adaptive system has two responses. Have you heard of T-cells and B-cells? T-cells are white blood cells that recognize the pathogen attached to them and then secrete cytokines or chemical signals that tell B-cells to multiply. B-cells produce the antibodies we mentioned. Together, they provide a great team effort. Antibodies attach to foreign substances so the immune system can eliminate them. Every antibody is specific to a particular substance or bacteria. Your body is a very smart system. Think of this as a lock and key, one bacteria will fit inside the antibody made specifically for it. Autoimmunity happens when this key is made for healthy cells and tissues, and the good guys get captured for elimination. By looking at a person's antibodies, it can often be determined if they have an allergy and infection or an autoimmune disease. Here's the fun fact, did you know that healthy bacteria can impact the immune system as well? In addition to helping its digest, even more of our food, will also synthesizing vitamins. The bacteria in our gut are constantly communicating with the immune system by sending chemical signals that help determine when pathogenic bacteria have gotten out of line or grown out of control. Bacteria can produce metabolites that up or down regulate the immune system. The common thought has always been there. Our immune system developed to ward off bacteria, but in reality, the bacteria in our gut may be essential to not only building our immune system, but helping it function day to day. The immune system and bacteria exists in interplay with each other and regulates each other. We don't yet know exactly how this works, but we're learning about the cross communication that's happening between our immune cells and the gut bacteria. It's as if they say things like, "Hey, are there pathogens out there? Do I need to send some anti-microbial peptize to take care of the job?" This is part of the innate immune function. Our friendly gut bacteria had been educating our immune system from birth on who to lookout for and who is okay to keep around. Beneficial gut bacteria can be both pro-inflammatory or anti-inflammatory, depending on what's needed. Bacteria send signals to the immune system that tell it whether or not inflammation is needed. Dysbiosis of gut bacteria can disrupt the immune system by altering the way bacteria communicate via chemokines and cytokines. The chemical signals that tell the innate and adaptive immune systems how to respond whether that is with attacking cells or bacteria or inflammation. Short-chain fatty acids, the byproducts that bacteria produce can also regulate immunity by sending signals to the immune system and the mucosal lining. Reduced bacterial diversity can lead to an immune system that overreacts to antigens. This can lead to autoimmune responses or allergies. Why? Think of it this way. It says, "If the immune system missed out on early training and so it doesn't recognize that these supposed offenders are okay and then it's fine to relax." Also, back to the hygiene hypothesis, something the immune system has less to do these days, so it's prone to overreacting. Essentially, our lives have become so clean that the immune system has started to attack itself. Now remember, this is just a hypothesis, but it is one possible explanation for why autoimmune issues are largely a western phenomenon. In studies where germ-free mice, these mice are more susceptible through infections. They also have significant holes in their gut lining, thinner walls, and defects in antibody production. Their Peyer's patchers are smaller, but when scientists put bacteria back into these mice, their mucosal lining in immune system seem to be restored. This implies good news for two reasons. It means that gut lining is repairable and that there is room for innovative therapies in the future. So why is all this important for gut health? There are two types of conditions that are ramped in our list of chronic diseases in the gut, autoimmune and autoinflammatory. We'll cover these in detail in another lecture. In this lecture, we laid the ground work by going over the two parts of the immune system. To recap, these are the innate and the adaptive immune systems. The innate system is the first responder beyond the gut wall and it works to quickly protect the body by killing off whatever is around it. The next and smarter line of defense is the adaptive immune system, which strategically uses its memory of past invaders to form its plan of attack. We talked about a lot of details in this lecture, but don't worry about memorizing all of the terms or specifics. The key takeaway point of this lecture is that a large part of gut health depends on having a healthy gut immune system. With so many conditions being tied back to the gut, we can begin to understand why. Through the gut, we take in the building blocks of cellular life and it's also where we protect against illness. The point of mentioning this is to be aware of the importance of the gut and how it may be connected to our overall health and wellbeing. We're now in another layer deep into the meaning all disease begins in the gut. As a Health Coach, I hope you're inspired because the best way to alter the gut is through diet and lifestyle. This is where your work can literally change the health of the world. Have you ever noticed the connection between your immune system and your gut? Do you tend to get sick often and have allergies or gut issues? How about your clients? Head on over the Facebook group to share your experiences. We can't wait to hear from you. Thanks for watching and see you next time.

Video Details

Duration: 14 minutes and 36 seconds
Language: English
License: Dotsub - Standard License
Genre: None
Views: 5
Posted by: ninaz on Mar 22, 2018

The Immune System in Your Gut_Final

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